Process and device for sterilizing by flaming containers for pharmaceutical preparations

ABSTRACT

Containers for pharmaceuticals can be sterilized by flaming, if the flames burn in a laminar-flow current of air, with little risk of contamination. A device for flame-sterilizing such containers is fitted out with means to produce a laminar-flow air current through the sterilizing part of the device.

United States Patent 1191 1111 3,721,525 Hortig et a1. 1 1March 20, 1973 PROCESS AND DEVICE FOR [56] References Cited AMING UNITED STATES PATENTS PHARMACEUTICAL PREPARATIONS 3,616,252 10/1971 Forel ..21/78 X [75] Inventors: Hans-Pair Hortig, Frankfurt am OTHER PUBLICATIONS 2 fig' 'ng zggf Remingtons Pharmaceutical Sciences, 13:11 Ed. a y Mack Publishing Co., Easton, Pa., (1965) pp. [73] Assignee: Farbwerke Haechst Aktiengesell- 364-365.

schaft vormals Meister Lucius 81 Bruning, Frankfurt am Main, Primary Examiner-Morris O. Wolk Germany Assistant Examiner-Warren Bovee 22 Filed: y 15 1971 Attorney-Curtis, Morris & Safford [21] Appl. No.: 162,974 157 ABSTRACT 1 Containers for pharmaceuticals can be sterilized by 58.31 ..21/2, 2 "79,322: flaming, if the flames bum in a laminapflow current of I u 1 e v t t t I I s Q u u h l't k f A f 581 Field of Search ..21/2,79-, 78, 85,92, 93, 111, mammamn dev'ce 21/112, 117, 122', 263/19 A; 43l/D1G. 100, DIG. 106

flame-sterilizing such containers is fitted out with means to produce a laminar-flow air current through the sterilizing part of the device.

2 Claims, 1 Drawing Figure PATENIEnlAnzolsu 3,721,525

INVENTORS HANS-PETER Home KARL-FRIEDRICH SCHUTZ BY I v ATTORNEYS PROCESS AND DEVICE FOR STERILIZING BY FLAMING CONTAINERS FOR PHARMACEUTICAL PREPARATIONS The present invention provides a process for sterilizing by flaming containers for pharmaceutical preparations, especially ampoules; it also provides a device to carry out the said process.

The so-called flaming constitutes a very economic process which was used in industry for a long while to sterilize containers, especially ampoules. In said process, the containers were passed at a definite distance over flames, heated by the hot exhaust gas and thus'sterilized.

The aforesaid process had the disadvantages that the flames always formed soot, although a small quantity only, and additional foreign particles were introduced into the sterile zone by the gradual scaling of the burner. Hence, flaming was abandoned because of the modern requirement with respect to purity of the sterile zone not being met. Measurements have proved that the hot exhaust gas contained up to 2 X particles having a size greater than 0.5 micron per 3 liters.

In has now been found that containers for pharmaceutical preparations can be sterilized by flaming without danger of contamination by foreign particles by passing them through the current of exhaust gas over the tip of one or several flames burning in a laminar-flow current of air, said current having a velocity of flow in the range of from 0.05 to 0.3 meter per second.

It is surprising that the flames burn at all in a laminarflow current of air as in such a flow an exchange of substances practically does not take place in a direction perpendicular to the direction of flow. It is furthennore surprising that in the flaming process according to the invention no soot is formed. The particles were counted in the zone through which the exhaust. gas passed and the following values were found, which are at least by a factor of 50 below the values requested by the US Federal Standard 209 a for clean rooms.

Fuel gas propane methane hydrogen particles greater than 0.5 micron per 3 liters 0.2 0.2 0.1

of air The device according to the invention suitable to sterilize containers by flaming essentially consists of a burner, transporting means to transport the containers continuously or discontinuously over the burner and means to produce a purified air current through the sterilizing zone, and is characterized by a distributing device arranged at the air inlet into the sterilizing zone to cause the air to flow through the said zone in a laminar flow.

The distributing device may simultaneously act as filter for the air current. Sometimes, it may be more advantageous, however, to install the filter at another place. In this case, a plate with holes or slits may be used as distributing device.

A device in accordance with the invention will now be described, by way of example only, with reference to the accompanying drawing, which is a cross section through the sterilizing zone of a washing and filling device for glass ampoules.

Blower l aspirates an air current through a preliminary filter 2 and conveys the said current throu h main filter 3 and air duct 4 to the sterilization cham er. At

the inlet of the sterilization chamber a distributing device 5 is mounted which transforms the arriving turbulent air current into a current with laminar flow 6. Fuel gas is supplied through burner pipe 7. Numeral 9 designates the transporting means, in the present case a turnable plate, the rim of which is provided with recesses wherein the ampoules 8 are suspended in a manner such that they pass by the tips of the flames of burner 7. The hot exhaust air escapes at 10. An access to the sterilization chamber-if need should arise-is ensured by a flap l I.

On principle, the separate distributing device 5 may be dispensed with and its function may be taken over by main filter 3. With a separate distributing device it is more simple, however, to mount and exchange the main filter.

The production of a laminar flow is known in the art and has been described by B.J.M. Pilcher, Ingenieur Digest 9, (1968), pages 71 75 and l-I.P. Hortig Chemie lngenieur Technik, 19 (1.969). Distributing devices to produce such laminar flows or main filters that can take over their function are commercially available.

What is claimed is:

1. A process for sterilizing by flaming containers for pharmaceutical preparations which comprises passing the containers through the exhaust gas over the tip of one or several flames burning in a laminar-flow current of air, said current having a velocity of flow in the range of from 0.05 to 0.3 meter per second.

2. A device for carrying out the process of claim 1, comprising a sterilization chamber with burner and transporting means to transport the containers over the burner and means to produce a purified air current in the said sterilization chamber, wherein at the inlet of the air current into the sterilization chamber a distributing device is mounted to cause the air current to pass the sterilization zone in a laminar flow.

* l l t t 

2. A device for carrying out the process of claim 1, comprising a sterilization chamber with burner and transporting means to transport the containers over the burner and means to produce a purified air current in the said sterilization chamber, wherein at the inlet of the air current into the sterilization chamber a distributing device is mounted to cause the air current to pass the sterilization zone in a laminar flow. 